集成嵌入式储能的双馈风力发电系统功率控制

Power Control of DFIG Based Wind Power System Incorporated with Embedded Energy Storage

风能输出功率的波动性和间歇性源于原动力风的自然特性,其接入系统会给电网稳定性和电能质量带来不利的影响。结合双馈发电系统采用背靠背变流器且具有直流母线的特点,提出一种基于嵌入式能量存储系统抑制风电出力波动的控制方法。该储能系统不仅电气上可嵌入双馈系统直流侧,而且物理上也可嵌入实际系统,其灵活的功率吞吐能力可依据风速变化补偿双馈发电系统输入电网的功率波动。设计了相应的控制策略,通过经典风力四分量模型和电网电压降落的仿真算例,对集成嵌入式能量存储的双馈发电系统的运行特性进行了仿真。仿真结果表明,所提出的拓扑结构和功率控制策略能够很好地改善并网风力发电系统的电能质量和稳定性。

Fluctuation and intermittence are the characteristics of wind energy,which originate from the natural feature of wind. With this variable power flowing into grid,the grid stability and power quality would be impacted. Because doubly-fed induction generator （DFIG） based wind system adopts two back-to-back voltage source converters and a DC bus,a power control method is proposed based on embedded energy storage （EES） system to smooth short-term fluctuations in the wind farm output. Not only can the EES be embedded into the DC side of DFIG electrically,but also can insert the DFIG physically. Taking the natural characteristic of wind into consideration,EES is capable to damp the fluctuant power into grid with its flexible power handling capability. The corresponding control strategy is designed. Taking the classical four-component wind model and grid voltage disturbance condition for example,the operational characteristic of DFIG based wind power system incorporating EES is simulated. Simulation results show that the power quality and stability of wind system connected to power grid can be improved by embedded energy storage.